Doweled expansion joint



March 8, 1966 c. M. JAHN DOWELED EXPANSION JOINT Filed Nov. 2, 1962 wwA/wmm Fig.

Fig. 4

6 INVENTOR.

CARL M. AHN y ATTORNEY 35 Fig. 5

United States Patent Ofiice This invention relates to the art and practice of monolithic constructions, and more particularly to the organization of massive emplacernents of initially-plastic materials, such as concrete pavement slabs, and the like, subject to temperature-induced expansion and contraction, and has as an object to provide a novel and improved, preformed, expansion joint suited for permanent incorporation in such empl-a-cements with facility and advantage.

A further object of the invention is to provide a novel and improved expansion joint for concrete slabs, and the like, that is amenable to expedient prefabrication in a form convenient and practical of installation for use.

A further object of the invention is to provide a novel and improved expansion joint for concrete slabs, and the like, that effectively preserves initial correlation of the masses thereby separated.

A further object of the invention is to provide a novel and improved expansion joint for concrete slabs, and the like, that accommodates and facilitates interdovveling of the masses thereby separated.

A further object of the invention is to provide a novel and improved expansion joint for concrete slabs, and the like, that is yieldable to applied compressive stress while protecting and preserving the initial integrity of the exposed slab corners thereby separated.

A further object of the invention is to provide a novel and improved expansion joint and slab dowel combination characterized by enhanced facility and practicality of use.

A further object of the invention is to provide a novel and improved construction and operative correlation of elements in and as an expansion joint for concrete slabs, and the like.

A further object of the invention is to provide a novel and improved construction and operative correlation of elements in and as a doweled expansion joint for concrete slabs, and the like.

A further object of the invention is to provide a novel and improved doweled expansion joint for concrete slabs, and the like, that is simple and economical of production in advance of and in condition for use, that functions where employed to promote important conservation of time and labor, that is applicable with inherent advantage in many and diverse particular structural installations, and that is positive and efiicient in attainment of the ends for which designed.

With the foregoing and other objects in View, my invention consists in the construction, arrangement, and operative combination of elements as hereinafter set forth, pointed out in the appended claims, and illustrated by the accompanying drawing, in which:

FIGURE 1 is a fragmentary, perspective view, partially in section, of a typical embodiment of the invent-ion in use association with contiguous pavement slabs.

FIGURE 2 is a transverse section, on a relatively-enlarged scale, through the joint feature according to FIG- URE l as operatively correlated with a dowel component, a stake as engaged to posit-ion and support the joint being indicated by broken lines.

FIGURE 3 is a fragmentary detail view, partially in section and on a further-enlarged scale, of one capped end of the dowel component shown in the preceding views as arranged within the contemplation of the invention to inhibit premature or inadvertent displacement of the cap.

Patented Mar. 8, 1966 FIGURE 4 is a view similar to FIGURE 3 illustrating another arrangement within the contemplation of the invention for inhibiting displacement of the cap relative to the dowel.

FIGURE 5 is a view similar to FIGURES 3 and 4 showing yet another arrangement within the contemplation of the invention for inhibiting displacement of the cap relative to the dowel.

FIGURE 6 is an elevational view of a dowel conforrnation alternative to that shown in the preceding views.

Occasion for and the practices conventionally incident to use of expansion joints integrated with and to separate contiguous concrete slabs, and the like, are established and known beyond reason for elaboration herein. The practicality of preformed expansion joints suited for installation to serve as a form element determining one end of an abutting slab surface, to cooperate with dowels intercoupling the contiguous slabs, and to accommodate temperature-induced linear expansive and contractive shift of the contiguous slabs is fully exemplified by the several such joints commercially available. However, the potential for improvement with respect to preformed expansion joints is far from exhausted, since there are factors of economy, use facility, preservation of slab margin integrity, permanence of slab surface correlation, and long-term dependability as yet unresolved, hence the in stant invention is directed to the provision of a unique expansion joint and joint and dowel combination distinguished by important practical and functional advantages. Since a significant area of expansion joint use is that having to do with pavements, whether exterior or interior, the instant invention is illustrated and hereinafter described in adaptation to such use, though it is to be understood that the principles and features so specifically disclosed have capability in other areas of construction and that the contemplation of the invention as determined by the scope of the appended claims includes and embraces the entire field of its applicable use without restriction deriving from the exemplary disclosure thereof.

A principal and distinctive feature of the expansion joint of the invention is an elongated, substantially-rigid, imperforate plate member It} integrally formed, as by bending, from thin metal sheet material to provide a longitudinally-straight strip of uniform width equivalent to the thickness of the slabs wherewith the joint is to be associated, which strip is characterized by a unique transverse conformation peculiar to the purposes and advantages of the invention. As clearly represented by FIGURE 2, the stri form of the plate member 10 is centrally and laterally offset as a wide, shallow arcuate trough llll extending the full length of the member in marginal conjunction with and between fiat, coplanar webs I2 and 13 which border, respectively, the upper and lower margins of the member. Determining the lateral extent of the web 13 an integral flange 14 outstands perpendicularly therefrom at the concaved side of the plate strip fully along and to establish the lower margin of the member 16 and the upper margin of the member is established parallel to the flange 14 with limitation of the lateral extent of the web 12- by a fold of the web material over and upon itself at the concaved side of the strip to provide a beaded edge 15 suited to function as a gauge for screeding of a contiguous slab surface therealong. The strip material folded to overlie the web 12 is directed laterally and inwardly thereof as a narrow band 16 contiguous to and coextensive with the edge 15, which band merges at its inward margin with the inclined floor 17 of a channel opening upwardly in overhanging relation with the flange 14 along the beaded edge 15 between the band 16 and an outer boundary 18 of inverted U-shape in transverse section defining a channel spacedly overhanging and opening toward the flange 14. The floor 17 of the upwardly-opening channel is inclined to slope outwardly and downwardly from its attachment to the band 16, whereby to provide that forces tending to constrict the open width of the so-fioored channel may be but moderately opposed as said floor yields through flexing of the strip material to adjustment of its angle of inclination.

Organized as shown and described, the plate member is adapted to position and support a heavy mat 19 of compressible, weatherand moisture-resistant material, such as impregnated felt, tar compositions, and the like, commonly availed of as expansion joint fillers, which mat is conformably applied to the concaved side of the plate member with one of its edge margins resting upon the flange 14 and its other edge margin overlapped on the web 12 beneath and out of engagement with the inclined channel floor 17 which is hence maintained in condition to flex as above set forth. In an appropriate thickness approximating the width of the channel floor 17, the mat 19 exposes at its engagement with the flange 14 a spaced succession of rectangular apertures 20 intersecting said flange for the slidable accommodation of fiat metal stakes 21 whereof the upper ends are receivable within the downwardly-opening channel of the boundary 18, so that when a stake 21 is entered through one of the apertures 20 to engagement of its upper end within the channel of the boundary 18 it serves to secure and retain the marginal zones of the mat 19 in overlying contact with the plate member webs 12 and 13, as represented by the broken line showing of FIGURE 2.

The expansion joint and stake combination thus far described is adequate for practical and expedient use in many situations where expansion joints are needful and is applicable to such use in the rather obvious manner typified by FIGURE 1. In connection with the placement of concrete pavement slabs requiring separation by expansion joints and given a supply of the joint units of the invention having a Width from flange 14 to beaded edge corresponding to the slab thickness, suitable lengths, and complementary stakes 21, the said stakes are driven into the sub-grade 22 in alignment with the position of the desired joint and in a spacing correlated with that characterizing the apertures through the flange 14 to registration at their upper ends with the finish plane desired for the upper surface of the adjacent pavement slab, whereafter a joint unit length comprised as above set forth to include a mat 19 is applied to and for support by the row of aligned stakes which are individually entered through the appropriate apertures 20 of the flange 14 to ultimate engagement of their upper ends within the downwardly-opening channel of the boundary 18 as the unit is lowered on and in guided relation with the stakes to its position of use with the flange 14 resting upon or close to the sub-grade. Secured in position of use by the stakes 21 as above described, successive lengths of the joint units may be end-abutted for any desired combined length wherein the plate members 10 establish a form wall against which a slab may be poured and the beaded edge 15 provides a surface grade guage to which the slab material may be screeded in a usual manner. Contiguous slabs 23 and 24 are conventionally developed at and against the opposite sides of the positioned joint unit, or units, to therein permanently embed. the plate member 10 and stakes 21 with the mat 19 interposed as a cushion between the slabs and the channel between the band 16 and boundary 18 opening upwardly from its inclined floor 17 where it separates the adjacent upper surface corners of the slab to receive and retain suitable material, such as pitch, asphalt, sand, and the like, incharged to the channel as a filler renewable as occasion may require. Consequential to the organization and use of the improved joint units, the opposed end margins of the contiguous slabs formed there-against are conformably nosed and channeled to a coaction that resists relative elevational displacement, the opposed upper surface corners of the slabs are braced by the beaded edge 15 and the boundary 18, and the inclined floor 17 of the channel separating said corners yields to the compressive stresses imposed by the slabs with concomitant ejection of filler material to further protect said corners against impairment, all of which contribute to preserve and to enhance the initial integrity of the slab surfaces with such minimal interruption thereof as is inconsequential to the uses for which the pavement is designed. 4

Interlock of the contiguous pavement slabs against relative elevational displacement may be, and has been, promoted by the use of dowels traversing conventional, and other, expansion joints to embedment in the material of the slabs separated by the joint, and such practice may feasibly supplement the properties of the improved joint units hereinabove described as represented by FIG- URES 1 and 2 wherein is shown a conventional straight, rigid dowel bar 25 terminating in slidably-associated and caps 26 entered perpendicularly and centrally through the plate member 10 and mat 19 to project at the opposite sides of the joint unit for reception and permanent embcdment in the material of the separated slabs 23 and 2d, the said bar 25 being positioned and supported in its intended use relation with the joint prior to and during development of the slabs by stakes or chairs, not shown, commonly availed of for such purpose. The dowel bar 25 is disposed with its length generally parallel to the line of relative shift occasioned by expansion and contraction of the slabs connected thereby and is furnished with the caps 26 to accommodate such axial shift of the bar relative to either one or both of the associated slabs as may be needful to tolerate relative shift of the slabs without disruptive effect therewithin, in which connection it is practical to coat the bar with a dressing that obviates bonding of the slab material thereto and to expose the exteriors of the caps to bonding coaction with the slab material, whereby said caps are constrained to shift with their respective slabs in a variable telescoping coaotion with the ends of the bar. Since it is known that some relative tilting of contiguous pavement slabs may occur about a hinge axis at the expansion joint with possible disruption of slab material where engaged by the bar 25, the invention comprehends the provision of an axially arcuate bar 25', represented by FIGURE 6, employable in substitution for the straight bar 25 to function, as expediently placed, to accommodate bar shift with some toleration of expected slab tilt.

Incident to placement of the dowel bars 25 and 25' and the operations of slab development thereabout the caps 26 slidably terminating the bars may become detached or displaced with nullification or serious impairment of their functions, in avoidance whereof provision is made for initial attachment of the caps to the bar with an adequate original security subsequently yieldable to the temperature-induced forces acting through the slabs to shift the bar relative to either or both of its caps. As represented by FIGURE 3, a shallow, annular groove 27 may be formed on and inwardly adjacent the end of the bar to register with the desirably-positioned inner end of the associated cap 26, which may or may not be charged with compressible, possibly lubricating, material 28, and the open, inwardly-directed end of the cap crimped into engagement within said groove, whereby to effectively conjoin the cap and bar for subsequent detachment in reaction to axially-applied forces. Alternative to the foregoing, as in FIGURE 4, one or more dimples 29 may be punched into the appropriate overlap of the cap on the bar with corresponding indent of the bar material and consequent yieldable attachment of the cap to the bar effective to realize the purpose of the association; while in FIGURE 5 is shown, a shallow, annular groove 30 formed in the bar to underlie the appropriate overlap of the cap thereon, a reference mark 31 on the bar for locating registration with the inward end of the cap and,

desirably although not necessarily, a reference line 32 circumferentially of the cap exterior in registration with and to locate the groove 30 when the end of the cap is aligned with the mark 31, whereby to provide that dimples 33 punched into the cap overlay at the mark 32 will serve in engagement within the groove 30 to yieldably latch the cap to the bar in attainment of the purposes and realization of the advantages above set forth.

Since changes, variations, and modifications in the form, construction, and arrangement of the elements shown and described may be had without departing from the spirit of my invention, I wish to be understood as being limited solely by the scope of the appended claims, rather than by any details of the illustrative showing and foregoing description.

I claim as my invention:

1. In an expansion joint of the character described having an elongated, uniform-width strip of substantially rigid sheet material formed with a continuous arcuate trough ofiset longitudinally and centrally thereof and a mat of compressible material conformably overlying the strip face concaved by said trough, the combination therewith of an integral flange normal to the plane of said strip outstanding along the full length of one edge margin thereof from the strip face concaved by the trough in a width laterally of the strip exceeding the thickness of said mat, said flange providing a seat for the adjacent edge of the mat and being formed with a succession of like apertures for the reception of stakes spaced apart longitudinally thereof in alignment parallel to the adjacent strip face and outwardly from the latter a distance approximating the thickness of the mat, whereby stakes entered through said apertures transverse of the strip inhibit separation of the mat from its edge support on said flange as an overlay to the strip, an integral laterallyand outwardly-opening channel spacedly opposed parallel to said flange along the full length of the other edge margin of said strip in a separation from the adjacent edge of the mat, and an integral laterallyand inwardly-opening channel along the full length and bounding the side of said outwardly-opening channel remote from the strip in overhanging registration with the aligned apertures inof the mat, and an integral laterallyand inwardly-openchannel is adapted to embrace the upwardly-directed ends of stakes entered through the apertures of the flange and thereby position and support the strip with concomitant retention of the mat in covering relation with the troughed 'face thereof and said upwardly-opening channel defines a recess depressed relative to the upwardly-directed margin of the strip for reception of joint-sealing material.

2. The combination according to claim 1, wherein said outwardly-opening channel is defined between spacedlyparallel, fiat side walls conjoined by a fiat floor inclined laterally therebetween, whereby compressive stresses applied to the channel side walls are accommodated through flexure at the floor and wall conjunctions.

3. The combination according to claim 1, wherein said outwardly-opening channel is defined between spacedlyparallel, flat side walls conjoined by a fiat floor inclined laterally therebetween inwardly of the width and away from the adjacent edge margin of the associated strip, whereby compressive stress is applied to the channel side walls are accommodated through flexure at the floor and wall conjunctions attended by retraction of the channel side wall remote from the strip inwardly of the strip width.

References Cited by the Examiner UNITED STATES PATENTS 1,571,700 2/1926 Burrell 94-18 1,711,934 5/ 1929 Fischer 94-18 1,902,944 3/1933 Fischer 94-182 1,942,494 l/ 1934 Robertson 94-8 2,015,340 9/1935 Fischer 94-18 2,027,516 1/ 1936 Burrell 9418 2,062,654 12/1936 Jacobson 94-18 2,540,251 2/ 1951 Fischer 94-18 3,059,553 10/1962 Woolley 94-18 CHARLES -E. OCONNELL, Primary Examiner. JACOB L. NACKENOFF, Examiner. 

1. IN AN EXPANSION JOINT OF THE CHARACTER DESCRIBED HAVING AN ELONGATED, UNIFORM-WIDTH STRIP OF SUBSTANTIALLY RIGID SHEET MATERIAL FORMED WITH A CONTINUOUS ARCUATE TROUGH OFFSET LONGITUDINALLY AND CENTRALLY THEREOF AND A MAT OF COMPRESSIBLE MATERIAL CONFORMABLY OVERLYLING THE STRIP FACE CONCAVED BY SAID TROUGH, THE COMBINATION THEREWITH OF AN INTEGRAL FLANGE NORMAL TO THE PLANE OF SAID STRIP OUTSTANDING ALONG THE FULL LENGTH OF ONE EDGE MARGIN THEREOF FROM THE STRIP FACE CONCAVED BY THE TROUGH IN A WIDTH LATERALLY OF THE STRIP EXCEEDING THE THICKNESS OF SAID MAT, SAID FLANGE PROVIDING A SEAT FOR THE ADJACENT EDGE OF THE MAT AND BEING FORMED WITH A SUCCESSION OF LIKE APERTURES FOR THE RECEPTION OF STAKES SPACED APART LONGITUDINALLY THEREOF IN ALIGNMENT PARALLEL TO THE ADJACENT STRIP FACE AND OUTWARDLY FROM THE LATTER A DISTANCE APPROXIMATING THE THICKNESS OF THE MAT, WHEREBY STAKES ENTERED THROUGH SAID APERTURES TRANSVERSE OF THE STRIP INHIBIT SEPARATION OF THE MAT FROM ITS EDGE SUPPORT ON SAID FLANGE AS AN OVERLAY TO THE STRIP, AN INTEGRAL LATERALLY AND OUTWARDLY-OPENING CHANNEL SPACEDLY OPPOSED PARALLEL TO SAID FLANGE ALONG THE FULL LENGTH OF THE OTHER EDGE MARGIN OF SAID STRIP IN A SEPARATION FROM THE ADJACENT EDGE OF THE MAT, AND AN INTEGRAL LATERALLY - AND INWARDLY-OPENING CHANNEL ALONG THE FULL LENGTH AND BOUNDING THE SIDE OF SAID OUTWARDLY-OPENING CHANNEL REMOTE FROM THE STRIP IN OVERHANGING REGISTRATION WITH THE ALIGNED APERTURES INOF THE MAT, AND AN INTEGRAL LATERALLY - AND INWARDLY-OPENCHANNEL IS ADAPTED TO EMBRACE THE UPWARDLY-DIRECTED ENDS OF STAKES ENTERED THROUGH THE APERTURES OF THE FLANGE AND THEREBY POSITION AND SUPPORT THE STRIP WITH CONCOMITANT THEREBY POSITION AND SUPPORT THE STRIP WITH CONCOMITANT RETENTION OF THE MAT IN COVERING RELATION WITH THE TROUGHED FACE THEREOF AND SAID UPWARDLY-OPENING CHANNEL DEFINES GIN OF THE STRIP FOR RECEPTION OF JOINT-SEALING MATERIAL. 